If you mean the tongue-jack dolly wheel, I'd remove it as it is for temporary use. My TH doesn't have one, but I did own a smaller trailer with a dolly wheel. During lengthy storage, I'd remove the wheel and place a wood block under the tongue jack.
As for the tires, sitting the tires on concrete for any length of time (such as over the winter), is not good for the tires. Concrete leaches the oils out of the rubber. Place some type of vapor barrier between the tires and the concrete...wood or plastic. I use Lynx Leveler under the tires.
Example photo below:
"It is What it is."
2006 Chevy Silverado Z-71, 4X4, 5.3L, 3:42, 100% Amsoil Lubricated
2005 Jayco Talon ZX24-E Toy Hauler
Prodigy P2 Brake Control
15K Putnam XDR Class V
10K Equal-i-zer WD Hitch
Firestone Ride Rite Air Bags
2005 Kawasaki KLR650
2009 Doodlebug Mini Bike